1. Field of the Invention
The invention relates to a vehicle differential apparatus.
2. Related Art
Conventionally, as a vehicle differential apparatus, there is known an apparatus which includes a differential case to be rotated by engine torque applied thereto, a pair of side gears arranged in parallel along a rotation axis of the differential case, a plurality of pinion gears respectively meshing with the side gears, and a pinion shaft for supporting the pinion gears (see, for example, JP-A-2010-053890).
In the vehicle differential apparatus disclosed in JP-A-2010-053890, a first pinion gear support member (pinion shaft) includes two projection portions respectively projecting axially from its two end portions. A case main body of the differential case includes two guide portions constituted of recessed grooves engageable with the projection portions. In assembling, the first pinion gear support member can be moved along the guide portions in a direction of axles. Also, the pinion gears are supported while inserted in insertion holes of a second plate-shaped pinion gear support member. The movement of the second pinion gear support member in the axle direction is controlled by a case cover to be mounted onto the case main body of the differential case.
In the above-structured vehicle differential apparatus of JP-A-2010-053890, the first pinion gear support member, the multiple pinion gears and the second pinion gear support member can be assembled outside the differential case to constitute an assembled body and the assembled body can be moved in the axle direction along the guide portions within the differential case and can be assembled to the differential case. Thus, the apparatus assembling operation can be simplified.
In addition, in the vehicle differential apparatus of JP-A-2010-053890, a thrust washer is disposed between an inner surface of the differential case and a back surface of the side gear. Thus, a friction resistance caused by sliding motion between the thrust washer and the side gear and a friction resistance caused by sliding motion between an inner peripheral surface of an insertion hole of the second pinion gear support member and an outer peripheral surface of the pinion gear act as differential limiting force for limiting the differential rotation of the paired side gears.
A vehicle differential apparatus of this kind is required to raise the differential limiting force in order to reduce a slippage of wheels and enhance a driving stability in a low μ road such as a bad road and an icy road. In addition, in the above-structured vehicle differential apparatus, a groove machining work to form within the differential case a recessed groove extending in the axle direction, when compared with a round hole machining work, takes time and labor and also is hard to secure work accuracy.